Tumour growth inhibition by calcitonin: role of the age of the animal and the hypocalcemic response.

Only young rats showed tumor growth inhibition by calcitonin treatment. This phenomenon appears related to its hypocalcemic properties and to structural rearrangement of the membranes which possibly produce permeability changes with a consequent functional impairment of the cell. These effects on the membranes are reflected by modifications of the binding of calcium and magnesium to the phospholipid fraction.